1. Field of the Invention
The present invention relates to an imaging optical lens assembly, and more particularly to a miniaturized imaging optical lens assembly applicable to electronic products.
2. Description of the Prior Art
In recent years, with the popularity of electronic devices having camera functionalities, the demand of miniaturized optical systems has been increasing. The sensor of a conventional optical system is typically a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor) sensor. As the advanced semiconductor manufacturing technologies have allowed the pixel size of image sensors to be reduced and compact, optical systems have gradually evolved toward the field of higher megapixels, there is an increasing demand for compact optical systems featuring better image quality.
A conventional image taking lens system used in mobile phone usually consists of three lens elements: from the object side to the image side: a first lens element with a positive refractive power, a second lens element with a negative refractive power and a third lens element with a positive refractive power, thus forming the so-called type of Triplet, such as the image taking lens system described in U.S. Pat. No. 7,436,603. Although such an arrangement can correct most of the aberrations caused by the optical lens system, it requires a relatively long track length of the optical lens system, so the lens structure must be lengthened and it will be difficult to maintain the objective of miniaturization of the image taking lens system.
A developed image taking lens system consisting of four or five lens elements has better image quality, however, there's an increasing demand for image quality, and the need for miniaturization of the handheld mobile device has been close to the lens size limit to production. Therefore, under the condition that image quality and small size cannot be taken into account synchronously, the image quality of the image taking lens system or the production yield will be reduced.
The present invention been made in order to solve the above-mentioned problems.